title: Biochemical and developmental characterization of carbonic anhydrase II from chicken erythrocytes.
abstract: BACKGROUND
  Carbonic anhydrase (CA) of the chicken has attracted attention for a long time because it has an important role in the eggshell formation. The developmental profile of CA-II isozyme levels in chicken erythrocytes has not been determined or reported. Furthermore, the relations with CA-II in erythrocyte and egg production are not discussed. In the present study, we isolated CA-II from erythrocytes of chickens and determined age-related changes of CA-II levels in erythrocytes.
  
  
  METHODS
  Chicken CA-II was purified by a combination of column chromatography. The levels of CA-II in the hemolysate of the chicken were determined using the ELISA system in blood samples from 279 female chickens, ages 1 to 93 weeks, 69 male chickens, ages 3 to 59 weeks and 52 weeks female Araucana-chickens.
  
  
  RESULTS
  The mean concentration of CA-II in hemolysate from 1-week-old female was 50.8 ± 11.9 mg/g of Hb. The mean levels of CA-II in 25-week-old (188.1 ± 82.6 mg/g of Hb), 31-week-old (193.6 ± 69.7 mg/g of Hb) and 49-week-old (203.8 ± 123.5 mg/g of Hb) female-chickens showed the highest level of CA-II. The levels of CA-II in female WL-chickens significantly decreased at 63 week (139.0 ± 19.3 mg/g of Hb). The levels of CA-II in female WL-chicken did not change from week 63 until week 93.The mean level of CA-II in hemolysate of 3-week-old male WL-chickens was 78.3 ± 20.7 mg/g of Hb. The levels of CA-II in male WL-chickens did not show changes in the week 3 to week 59 timeframe. The mean level of CA-II in 53-week-old female Araucana-chickens was 23.4 ± 1.78 mg/g of Hb. These levels of CA-II were about 11% of those of 49-week-old female WL-chickens. Simple linear regression analysis showed significant associations between the level of CA-II and egg laying rate from 16 week-old at 63 week-old WL-chicken (p<0.01).
  
  
  CONCLUSIONS
  Developmental changes and sexual differences of CA-II concentration in WL-chicken erythrocytes were observed. The concentration of CA-II in the erythrocyte of WL-chicken was much higher than that in Araucana-chicken (p<0.01).
authors.affiliation: Laboratories of Veterinary Physiology 1, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Sagamihara, Kanagawa, 252-5201, Japan. nishida@azabu-u.ac.jp
authors.forename: Toshiho
authors.initials: T
authors.lastname: Nishita
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Tomita
authors.forename: Takao
authors.initials: T
authors.lastname: Imanari
authors.forename: Nobutsune
authors.initials: N
authors.lastname: Ichihara
authors.forename: Kensuke
authors.initials: K
authors.lastname: Orito
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Arishima
mesh_terms: D000818:Animals; D024402:Carbonic Anhydrase II / Q000737:chemistry* / Q000378:metabolism*; D002645:Chickens / Q000254:growth & development / Q000502:physiology*; D004912:Erythrocytes / Q000201:enzymology*; D005260:Female; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D008297:Male; D012737:Sex Factors; D013997:Time Factors
chemical_list: D007527:Isoenzymes; D024402:Carbonic Anhydrase II